Reduction of aldehydes using trialkylboranes in ionic liquids

Grignard Reactions in Pyridinium and Phosphonium Ionic Liquids

“…The reductions of aldehydes and ketones by boranes in imidazolium [35] and phosphonium [36] ILs, as well as the sodium borohydride reduction of aldehydes and ketones in imidazolium ILs [37] and imidazolium ILs with water [38] has been reported, but to the best of our knowledge this report describes the first reduction of aldehydes in ILs in the presence of organometallic reagents.…”

“…In contrast when the reaction was conducted in pyridinium ILs 10a and 10b, also containing ether side chains, the reduction of aldehydes to alcohols was observed in the absence of an ethereal co-solvent, while the expected addition product occurred in the presence of diethyl ether. The reductions of aldehydes and ketones by boranes in imidazolium [35] and phosphonium [36] ILs, as well as the sodium borohydride reduction of aldehydes and ketones in imidazolium ILs [37] and imidazolium ILs with water [38] has been reported, but to the best of our knowledge this report describes the first reduction of aldehydes in ILs in the presence of organometallic reagents.…”

Understanding Organic Processes in Ionic Liquids: Achievements So Far and Challenges Remaining

“…These have included chiral epoxidations [102], reduction of aldehydes using trialkylborons [103], 1,3-dipolar cycloadditions [104], Baylis-Hillman reactions [28,105], Knoevenagel condensations [106], α-tosylation of enolizable ketones [107], Rosenmund-von Braun reactions [108], acetylation [109] and benzoylation [110] of nucleosides, aza-Markovnikov addition to alkenes [111], three component syntheses to give 3-alkyl-5arylmethylidene-1,3-thiazolidine-2,4-diones [112], conjugate addition of thiols to electron deficient alkenes [113], aromatic aminations [114], conversion of the acetates of Baylis-Hillman adducts to give trisubstituted alkenes [115], selective benzoylation of nucleosides with benzoyl cyanide [116], the synthesis of aromatic nitriles from aromatic aldehydes [117], the synthesis of N-substituted phthalimides [118], alkylation of thiazolidinediones [119], stereoselective conjugate additions [120], synthesis of 1,2-orthoesters of carbohydrates [121], Morita-Baylis-Hillman reactions [122], Huisgen cycloaddition to form 1,2,3-triazoles [123] and esterification of tertiary alcohols [124]. However, in each of these cases, no explanation for the different outcomes in ionic liquids was discussed.…”

Lipophilic M(α,α′-OC5H11)8phthalocyanines (M = H2and Ni(ii)): synthesis, electronic structure, and their utility for highly efficient carbonyl reductions

“…Although the band can be shifted to longer wavelength through fused-ring-expansion with benzene rings to form naphthalocyanine (Nc) [9] and then anthracocyanine (Ac), [10] the marked destabilization of HOMO level makes these compounds unstable and in the absence of peripheral substituents there are also issues with solubility. [12] Numerous methods have been developed to achieve this transformation selectively in the presence of other reducible functionalities [13] using trialkyl boranes with ionic liquid, [14] and metal such as gold [15] , manganese [16] , iridium [17] , platinum [18] , ruthenium [19] , rhodium [20] , osmium [21] . It is an important step in the synthesis of natural products, [11] bulk and fine chemicals.…”